Why don't all clouds produce rain?

A cloud is just an accumulation of mist. There is always water vapour in the air but during the summer there is more because the temperature is higher. It takes only a slight drop in temperature to make water vapour condense in air full of moisture. So when saturated warm air rises to an altitude where the temperature is lower, condensation takes place and we have a cloud. The droplets of water in a cloud have weight, so gravity gradually pulls them down and they sink lower and lower. As most of them fall, they reach a warmer layer of air, and this warmer air causes them to evaporate. So here we have clouds that don't produce rain. But suppose the air beneath a cloud is not warmer, but very moist air. Naturally, the droplets won't evaporate. Instead, the droplets will get bigger and bigger as more and more condensation take place. Pretty soon each droplet has become a drop and it continues falling downward and we have rain.

Fact file

Rainbows occur in the sky when drops of rain in the air act as prisisms to split the light into the seven colours of the spectrum. This usually happens just after a fall of rain.

resources: Tell me why (Chancellor Press)
image 1: https://www.australiasevereweather.com/photography/photos/1996/1204jd11.jpg
image 2: https://thumbs-prod.si-cdn.com/lTTjbgKf90_EU-cK5fmK0aVcqT0=/800x600/filters:no_upscale()/https://public-media.smithsonianmag.com/filer/58/59/58595ce8-2e34-4e19-ad04-b1de10715820/42-34984749.jpg

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